Quiet Icemaker and Dispenser

ABSTRACT

A nearly silent icemaker and dispenser for a refrigerator-freezer that can gently dispense uniform pieces of ice in a quiet controlled manner.

BACKGROUND OF THE INVENTION

A conventional icemaker and dispenser of the type that dispenses ice through an opening in the front of a home refrigerator-freezer is an extremely noisy, unreliable, and annoying device. It typically makes a batch of ice chunks by flowing water into a multi-cavity mold and then it noisily dumps them into a bin. If the mold is slightly overfilled as often happens, the chunks will be frozen together into a clump. As a result of temperature variations due to door openings or automatic defrost cycles, while sitting in the bin, the ice may further conglomerate into a large mass which must be broken apart before being dispensed.

A motorized auger is typically used to pull the ice forward where a whirling rotary hammer noisily smashes the ice apart into dispensable-sized pieces and propels them out a chute at disturbingly high velocity with enough force to smash delicate glassware. When a user inserts a container into the dispenser, the number, shape, and size of ice pieces coming out the chute at any given time is totally unpredictable, so the ice may overfill the container, or it may cause an ice jam and clog the chute. If that happens, the dispenser may keep running but no ice comes out of the chute. When the freezer door is opened, a huge pile of ice may fall out onto the floor. In some designs, an ice jam can push back on the dispenser actuator causing the dispenser to not shut off when the container is removed. If it is then switched over from ice to water, water will pour out and not shut off until the jam is cleared.

The entire system may take up well over a cubic foot of space inside the freezer section of the refrigerator. These systems are often unreliable and if some part of the unit fails, it may take considerable skill, tools, and time to repair the unit in place or to remove it and replace it.

BRIEF SUMMARY OF THE INVENTION

The invention disclosed herein employs a completely different method of producing and dispensing ice that eliminates most of the noise and gently dispenses uniform pieces of ice at predictable intervals.

A large array of single cavity molds is carried along a serpentine path by a belt or chain inside a rectangular housing. The molds move whenever a user requests ice by inserting a container into the dispenser. As a frozen mold reaches the front of the system the ice contained therein is quietly ejected from the mold and gently slides down a chute into the container. When the empty mold moves forward it is refilled with water and gradually freezes as it moves along the serpentine path. A user adjustable speed control could determine how rapidly the ice is dispensed.

Since each piece of ice is contained in its own mold until it is dispensed, it cannot get stuck to any other piece. Thus, no noisy auger or rotary hammer is needed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a serpentine array of the ice molds in a proposed embodiment.

FIG. 2 is a top view of a transport mechanism used to carry the ice along a serpentine path.

FIG. 3 is a top view of a horizontal plate that supports the transport mechanism. It also shows with dashed lines the location of a set of vertical guide walls below the plate that keeps the ice molds aligned and provides support for the horizontal plate. There is also a bottom cover (not shown) below the molds to protect them from interference.

FIG. 4 shows details of 3 round ice molds in their normal vertical orientation and 3 more tilted to their horizontal orientation for ejection of their ice.

FIG. 5 is the same as FIG. 4 only with squarish shaped ice molds.

FIG. 6 Is a block diagram of the electronic control system.

It should be noted that these are simplified drawings to illustrate the basic concepts. While they depict a proposed arrangement of the claimed elements, engineering and testing may lead to a somewhat different embodiment to improve performance, manufacturability, cost, etc.

DETAILED DESCRIPTION

FIG. 1 is a top view of one proposed embodiment with an array of 181 ice molds lined up in a serpentine path within a horizontal rectangular housing about 10″ by 20″. Item 102 a is the left side, 102 b is the front, 102 c is the right side, and 102 d is the back. The ice molds move forward along the left side, travel from left to right across the front, where the ice is ejected, and the molds are refilled with water and move backward along the right side. They then move forward and backward in alternate rows till they reach the left side. 103 a shows one of several straight vertical guide walls to keep the molds lined up and to keep alternate rows separated. 103 b shows one of several curved vertical guide walls to help the molds navigate the turns at each end of the serpentine path. These guide walls may not be necessary. If present, they may be slotted or perforated to facilitate air flow between the molds. A fan or blower (not shown) may be used to direct cold air at the molds to speed up the freezing process. These guide walls may be formed as part of the horizontal plate, part of the bottom cover, or as independent parts fitted between the plate and bottom cover.

A typical mold 104 a on the left side would be fully frozen, while a mold on the right 104 b would be freshly refilled with water and may not be frozen. If a large amount of ice is used in a short time, all the fully frozen ice could all get used up, and unfrozen or partially frozen molds could reach the ejection area. A fully frozen mold will be cooled close to zero degrees, but any mold that still contains liquid water will be close to 32 degrees. A temperature sensor (not shown) along the left side near the front would measure the temperature of each mold as it moves forward and would send a signal to the control system to prevent an unfrozen mold from reaching the front and causing a spill. When a frozen mold 106 reaches the front, a specially formed guide wall under the mold (not shown) tilts the mold sideways. Another specially formed guide wall 105 gently pushes forward on the bottom of the tilted molds to push the ice 108, 109 out of the mold and into a discharge chute mounted in the freezer door.

Instead of a passive guide wall to eject the ice, it may be preferable or even necessary to use active means such as a cam or lever to push the ice out more forcefully. A cam or lever could be driven by the transport mechanism to keep it synchronized with the motion of the molds.

It may be possible to simplify the process somewhat by not tilting the molds. In the simplified embodiment the molds stay vertical, and the bottom of the mold is pushed upward ejecting the ice out the top. A guide above the mold causes the ice to tip forward and fall into the discharge chute. However, that method might require too much additional height.

After ice is ejected from a mold 109, the mold drops back to its vertical orientation to be refilled. If only a single mold is being refilled, there is plenty of time to do it. However, if multiple molds are being emptied and refilled in quick succession while the transport mechanism may be running continuously, fill time is severely limited, and needs to be precisely timed to avoid dispensing water between the moving molds. Yet, if the mold is filled too fast, water may splash out. Thus, it may be necessary to have multiple valves and fill nozzles whereby each one fills a mold part way full as it goes by. Three fill valves and nozzles 110 are shown but more or fewer may be needed.

Depending on the size of the refrigerator-freezer, the size and shape of the icemaker and the number of molds contained therein may be different.

FIG. 2 shows the arrangement of the transport mechanism that moves the ice molds along their path. The transport may use a timing belt 201 a and several pullies 202 a, or a timing chain 201 b and several sprockets 202 b. The ice molds are suspended from the belt or chain by hangers which may include means to allow the molds to be tilted sideways for dispensing the ice.

Both sides of the belt or chain must alternately engage the pulleys or sprockets as it winds back and forth around them, so the hangers must be attached in a way that does not interfere. The spacing between the hangers should be an exact multiple of space between the teeth of the pulleys or sprockets.

The transport mechanism is mounted to the upper surface of a rectangular horizontal plate. A serpentine slot runs through the plate directly below the transport to provide a way for the hangers to extend down below the plate and connect to the ice molds and move them along under the transport. The continuous slot separates the plate into two pieces, and greatly weakens them both. A top cover is attached to the plate, bridging across the slot in multiple locations to strengthen the plate and to join the two parts together. The top cover also protects the transport mechanism from interference or contamination and provides operator safety. The curves near the front 203 may not be circular, so a fixed guide or a series of small idler wheels may be used to establish the shape of the desired curve. Springs may be employed to maintain suitable tension in the transport.

FIG. 3 shows the position of the serpentine slot 302 formed in the horizontal plate 301. It also shows the positions of the vertical guide walls 303 under the horizontal plate, as indicated by the dashed lines.

FIG. 4 shows a group of six round ice molds on their hangers 402 suspended from a transport belt or chain 401. Three of the molds are shown in their vertical orientation 403 and the other three are shown tilted to their horizontal orientation 404 for ice ejection.

FIG. 5 shows the same information as FIG. 4 only with squarish ice molds rather than round. Since 10 rows of molds are shown in a 10-inch-wide array, each mold would be slightly less than an inch square. The molds are depicted to be about as deep as they are wide, but they may be made deeper than shown to hold more water without it splashing out when the molds are moved by the transport. It is a goal to keep the total height of the icemaker to be not more than three inches, which is less than half the height of a conventional icemaker.

The individual ice molds would be formed from a durable material that remains flexible at cold temperatures such as silicone rubber, with a more rigid collar at the top where it attaches to the hanger. For simplicity, in most of the drawings the shape of each mold is shown as a plain cylinder. In practice, the molds would have to be wider at the top to facilitate ejection of the ice and will likely be made more squarish which would increase the packing density by about 20%. Because the sidewalls of the molds are tapered, ice is easily ejected from the mold by pushing up on the flexible bottom. For dispensing, the bottom of the mold may be tilted backward to a horizontal orientation so that the ejected ice is directed forward toward the front door of the freezer and into a dispensing chute. Ideally, the resilient mold material would spring back on its own to its original shape after the ice is ejected. If it fails spring back fully, water might overflow when the mold is refilled. To make sure this does not happen, a steel spring could be incorporated into each mold, or other means could be employed to force the mold back to its original shape. For example, a disk could be attached to the bottom of each mold and an angled slotted plate could intercept the disk after the ice is ejected and tug on the mold as it moves along to pull it back to its fully extended shape.

FIG. 6 shows a grooved disk 601 attached to the bottom of a mold. Since the silicone rubber mold material has a high coefficient of friction it could experience considerable drag rubbing against the guide wall that was trying to eject the ice. The grooved disk could be made of a material with very low friction and could engage a slot in the guide wall with very little drag making it easier to eject the ice. The slotted guide wall could then pull back on the disk to make sure the mold returned to its fully extended shape.

Because water expands by about 9% as it freezes, it would tend to cause the sides of the mold to bulge out, making ejection difficult. Careful design of the mold shape would prevent this problem by allowing the ice to slide upwards in the mold to accommodate the expansion. Another way to prevent side bulge would be to force the bottom to freeze first with the top freezing last. This can be accomplished by having a gentle heater on the underside of the horizontal plate. This would also prevent frost buildup from the liquid water evaporating and condensing on a cold plate. Forcing the molds to freeze from the bottom up may also cause the ice to be clearer due to less entrapped air. Clear ice is considered preferable for cocktails. Carefully directed cold airflow at the bottom of the molds could also help the process.

The belt or chain is moved along its path by a small motor that drives at least one of the pullies or sprockets. The motor starts and stops gently to avoid spilling water from the molds. The motor would most likely be mounted to the horizontal plate.

To simplify wiring, the ice maker may be plugged directly into a mating connector on the freezer door using a flexible ribbon cable. This reduces cost and complexity by avoiding the messy labor-intensive process of running the wires through a hollow door hinge.

In operation, it would be possible to get a single ice cube if desired. The transport would start up and move forward the distance of one mold and stop again. As the ice dropped down the chute, the previously emptied mold would get refilled. In this mode, it could dispense about one cube per second. If many cubes are needed quickly, the transport could run continuously, dispensing about two or possibly three cubes per second. Thus, the entire array of 180 cubes (weighing about 5 pounds) could be dispensed in 90 or perhaps 60 seconds.

Because this quiet icemaker is only about three inches high, two of them could be installed one above the other in a freezer and would still take up less space than a single old-style icemaker. It could even be purchased and installed later by the customer.

When the transport is running in continuous mode, the water filling the molds must turn on and off rapidly to avoid spilling water between the molds. With a single filling spout, each mold may only be in position for less than a half or even a third of a second, which may not be enough time for a complete fill. Thus, multiple filling spouts may be needed with each one doing a partial fill. While it might be possible to use mechanical valves driven by the transport mechanism, solenoid valves under microprocessor control would provide greater flexibility and precision. Some type of non-contact level sensor, perhaps ultrasonic, may be used to provide optimum or even variable fill level.

As with other icemakers built into refrigerator-freezers, a dispenser and operator control panel would be mounted in the freezer door, and the dispenser would also provide water. Crushed ice would be an option, with crushing means mounted within the dispensing chute. A pair of high-torque slow-turning rollers would gently crush each ice cube as it passed down the chute, again making a lot less noise than a conventional crusher.

FIG. 7 is a block diagram of the control panel functionality. The incoming water line and control valves need to be kept slightly above freezing at all times, so the layout should be very compact and well insulated to minimize the power needed by the heater. The heater under the horizontal plate only needs to be on while freshly filled molds are still unfrozen. Additional temperature sensors may be needed to determine when it is safe to turn this heater off. Once all the molds are frozen, the blower no longer needs to run. 

I claim:
 1. A very quiet ice maker and dispenser for a refrigerator-freezer comprising: a. An array of individual flexible molds to form ice of a controlled shape and size, b. a transport mechanism to quietly move said molds along a continuous horizontal serpentine path, c. an ejection location along said path where said ice may be ejected from a mold, d. said path generally arranged in several straight rows to fit within an essentially rectangular housing, e. an array of hangers, each hanger having an upper portion attached to said mechanism and a lower portion attached to a mold, f. a horizontal plate positioned between said mechanism and said molds to support said mechanism and to protect said molds from any mechanism-related contamination, g. said plate having a narrow serpentine slot directly below the mechanism to allow the hangers to slide along said slot in unison with the mechanism, h. an array of rotatable wheels to support and guide said mechanism along said serpentine path, i. an electric motor with means to drive at least one of said wheels to propel said mechanism along its path, j. a top cover to bridge across the slot of the horizontal plate in multiple locations and to cover and protect said mechanism, k. a bottom cover below said molds to protect them from interference as they move along their path, l. an array of vertical guide walls between said rows to keep the moving molds from interfering with each other, m. means to eject ice from one mold at a time as each mold is moved to the ejection location, n. a supply line to deliver potable flowing water to refill each empty mold after it passes the ejection location, said water having a temperature above freezing o. at least one valve to control the flowing of said water, p. at least one electric heater to prevent said water from freezing on its way to a mold, q. a first temperature sensor to monitor the temperature of the water, r. said plate having an electrically heated underside to prevent frost from building up due to evaporation from any unfrozen water in the molds, s. a second temperature sensor to monitor the heated underside of the plate, t. a third temperature sensor to monitor the molds as they approach the ejection location, u. at least one position sensor to monitor a mold as it is being refilled, v. an electrical connector with means to connect to a mating connector in a refrigerator-freezer, w. a plumbing fitting with means to connect to a mating plumbing fitting in a refrigerator-freezer, x. a housing to contain the earlier claimed parts with means to install said housing into a refrigerator-freezer.
 2. A device as in claim 1 wherein the mechanism is a timing belt, and the wheels are toothed timing pullies.
 3. A device as in claim 1 wherein the mechanism is a timing chain, and the wheels are sprockets.
 4. A nearly silent icemaker as in claim 1 which includes and works in conjunction with an electronic control panel and an ice dispenser chute to be mounted in a freezer door comprising, a. a power supply, b. a user interface providing user controls and indicators, c. electronic sensing circuitry responsive to said user controls, d. electronic drive circuitry generating control signals to operate said icemaker, e. a sensing circuit to monitor said first temperature sensor, f. a drive circuit to regulate said electric heater, g. sensing circuitry to monitor said second temperature sensor, h. drive circuitry to regulate said heated underside of the plate, i. sensing circuitry to monitor said third temperature sensor, j. drive circuitry to operate the transport mechanism, and to stop said mechanism if an unfrozen mold is approaching the ejection location, k. sensing circuitry to monitor said position sensor, l. timing circuitry to synchronize said valve(s) with the position of said molds, m. a discharge chute to catch ice as it is ejected from a mold and direct said ice into a user receptacle.
 5. Ice crushing means compatible with the device of claim 1 and located along said discharge chute and which may be enabled by said user interface to crush ice as it passes through said chute. 